First you have to make a clinical diagnosis based on clinical history which show the symptoms described above. We also have to inquire into the nature of the crisis, presentation, interval between crises, desencadentes, seasonal period, disease progression and a general pediatric anamnesis in order to be able to make a differential diagnosis of other respiratory diseases that may present with the same symptoms as asthma. In order to objectify the airflow obstruction, the diagnosis is functional, which is a respiratory function test (spirometry). It has the disadvantage that it requires the cooperation of the child and therefore performed in children over 6 years.
In every child in suspected bronchial asthma must perform baseline spirometry and bronchodilator (give the child to inhale a drug) to demonstrate that the airway obstruction is reversible (characteristic of asthma). Finally, an etiologic diagnosis, led to seek the cause that triggers the symptoms, to identify the cause is the most important step to control the disease.